The cloud predates similar blobs, known as Lyman-Alpha blobs, which existed when the universe was 2 billion to 3 billion years old. Researchers named their new find Himiko, after an ancient Japanese queen with an equally murky past.

Himiko holds more than 10 times as much mass as the next largest object found in the early universe, or roughly the equivalent mass of 40 billion suns. At 55,000 light years across, it spans about half the diameter of our Milky Way Galaxy.

Lyman-Alpha blobs remain a mystery because existing telescopes have a hard time peering so far back to nearly the dawn of the universe.

Himiko sits right on the doorstep of an era called the reionization epoch, which lasted between 200 million and 1 billion years after the Big Bang.

After making the initial sighting with the Subaru telescope in Hawaii in 2007, Ouchi and his colleagues followed up using instruments from the Keck/DEIMOS and Magellan/IMACS arrays.

Those spectrographic observations allowed them to pinpoint the signature of the ionized hydrogen gas and determine the distance and age of the mysterious Himiko.

"We never believed that this bright and large source was a real distant object," Ouchi said. "We thought it was a foreground interloper contaminating our galaxy sample. But we tried anyway."